Foundation Science Primary 3 Diversity

Jun Jie used a metal key to scratch a plastic ruler and a wooden block. The metal key left a scratch on both. What does this show about the metal key?

A The metal key is stronger than plastic and wood.
B The metal key is harder than plastic and wood.
C The metal key is more flexible than plastic and wood.
D The metal key is more transparent than plastic and wood.
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Worked Solution

Step 1: Hardness is the ability of a material to resist being scratched. Step [2-9]: A harder material can scratch a softer material. Step [2-9]: Since the key scratched both, it is harder than both.

Correct answer: The metal key is harder than plastic and wood.

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